The present invention relates to the encoding of video to convey plural-bit auxiliary information (e.g., for purposes of copy control, establishing ownership, or authentication), and more particularly relates to improvements redressing fixed pattern noise associated with such encoding.
In accordance with a preferred embodiment of the invention, a video is steganographically encoded to convey a plural bit message without introducing apparent fixed pattern noise. The video comprises plural frames, each of which includes plural rows of video data. The encoding effects a pattern of changes to a row of original video to yield a row of encoded video. But that rowxe2x80x94in a subsequent frame (e.g., the next frame)xe2x80x94is changed by a different pattern. Fixed pattern artifacts are thus avoided.
In some arrangements, the frames convey different messages. In others, the frames convey the same message, but the apparent effect is changed by different noise data used in the encoding.
The foregoing and additional features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.